Four Simple Ways to Read a File Line‑by‑Line in Shell Scripts

Method 1: Input Redirection

The simplest approach is to use a while read loop with input redirection. Create a file mycontent.txt containing sample lines, then write example1.sh:

#!/bin/bash
while read rows
do
  echo "Line contents are : $rows "
done < mycontent.txt

Running the script prints each line prefixed with the custom message.

Method 2: cat and Pipe

Use cat to output the file and pipe it into the while loop:

#!/bin/bash
cat mycontent.txt | while read rows
do
  echo "Line contents are : $rows "
done

The pipe feeds each line to the loop, achieving the same result.

Method 3: Filename as a Parameter

Pass the file name to the script via $1 and redirect input from that argument:

#!/bin/bash
while read rows
do
  echo "Line contents are : $rows "
done < $1

Invoke the script with ./example3.sh mycontent.txt to process any file.

Method 4: Using awk

One‑liner with awk can print each line with a prefix:

cat mycontent.txt | awk '{print "Line contents are: "$0}'

This command directly streams the file through awk without an explicit loop.

Conclusion

The article shows how to read a file line by line in Bash using four different methods, each useful in various scripting scenarios such as searching for strings or processing logs.